I think it's a few things. Not having to be validated by what others think of you - I spent too much of my young life worrying about what others think, but came to realise that everyone else is far too concerned with their own life and often worrying what others think of them - don't try and see yourself through a faulty lens.
I believe every human person has intrinsic value (it is faith based for me but doesn't have to be), and that we are all equally precious. As I got older I relaxed into myself more and stopped worrying so much.
The other thing that stole joy and self worth was comparison. Facebook can be a shocker for that so might be worth a break from it if you regularly look at it thinking everyone else is better or more talented or more beautiful or more popular than you. Comparison is indeed the thief of joy. It's learning to be comfortable in your own skin. In who you are, not who you think society thinks you should be.
Look to your strengths - not everyone has obvious talents but everyone has good bits of character - caring, hospitable, thoughtful, would go out of their way to help others etc.
Don't let a script of negativity play in your head. It's easy to do but can be conquered. Whenever you think a negative thought about yourself, counter it with something positive.
There are ways. Perhaps finding a group to go to or sometimes counselling can help.
All the best.